From boasting about the size of his penis on national television to releasing records of his high testosterone levels, President Trump’s rhetoric and behavior exude machismo. His behavior also seems to have struck a chord with some male voters. See, for example, the “Donald Trump: Finally Someone With Balls” T-shirts common at Trumprallies.

But our research suggests that Trump is not necessarily attracting male supporters who are as confidently masculine as the president presents himself to be. Instead, Trump appears to appeal more to men who are secretly insecure about their manhood. We call this the “fragile masculinity hypothesis.” Here is some of our evidence.

What is ‘fragile masculinity’?

Research shows that many men feel pressure to look and behave in stereotypically masculine ways — or risk losing their status as “real men.” Masculine expectations are socialized from early childhood and can motivate men to embrace traditional male behaviors while avoiding even the hint of femininity. This unforgiving standard of maleness makes some men worry that they’re falling short. These men are said to experience “fragile masculinity.”

The political process provides a way that fragile men can reaffirm their masculinity. By supporting tough politicians and policies, men can reassure others (and themselves) of their own manliness. For example, sociologist Robb Willer has shown that men whose sense of masculinity was threatened increased their support for aggressive foreign policy.

We wanted to see whether fragile masculinity was associated with how Americans vote — and specifically, whether it was associated with greater support for Trump in the 2016 general election and for Republicans in the 2018 midterm elections.

How we measured fragile masculinity

Measuring fragile masculinity poses a challenge. We could not simply do a poll of men, who might not honestly answer questions about their deepest insecurities. Instead, we relied on Google Trends, which measures the popularity of Google search terms. As Seth Stephens-Davidowitz has argued, people are often at their least guarded when they seek answers from the Internet. Researchers have already used Google search patterns to estimate levels of racial prejudice in different parts of the country. We sought to do the same with fragile masculinity.

We began by selecting a set of search topics that we believed might be especially common among men concerned about living up to the ideals of manhood: “erectile dysfunction,” “hair loss,” “how to get girls,” “penis enlargement,” “penis size,” “steroids,” “testosterone” and “Viagra.” (With the exception of “how to get girls,” these are Google “topics” rather than individual search terms. For instance, the topic “erectile dysfunction” includes searches for “erectile dysfunction,” “ED” and “impotence.”)

To validate this list of topics, we asked a sample of 300 men on Amazon’s Mechanical Turk platform whether they ever had or ever would search for them online. We found that scoring high on a questionnaire measuring “masculine gender-role discrepancy stress” — concern that they aren’t as manly as their male friends — was strongly associated with interest in these search topics. Although these men were not a representative sample of American men, their responses suggest that these search terms are a valid way to capture fragile masculinity.

We measured the popularity of these search topics in every media market in the country during the years preceding the past three presidential elections. In the map below, darker colors show where these searches were most prevalent in 2016.

We found that support for Trump in the 2016 election was higher in areas that had more searches for topics such as “erectile dysfunction.” Moreover, this relationship persisted after accounting for demographic attributes in media markets, such as education levels and racial composition, as well as searches for topics unrelated to fragile masculinity, such as “breast augmentation” and “menopause.”

In contrast, fragile masculinity was not associated with support for Mitt Romney in 2012 or support for John McCain in 2008 — suggesting that the correlation of fragile masculinity and voting in presidential elections was distinctively stronger in 2016.

The same finding emerged in 2018. We estimated levels of fragile masculinity in every U.S. congressional district based on levels in the media markets with which districts overlap. Before the election, we preregistered our expectations, including the other factors that we would account for.

In the more than 390 House elections pitting a Republican candidate against a Democratic candidate, support for the Republican candidate was higher in districts that, based on Google search data, had higher levels of fragile masculinity. However, there was no significant relationship between fragile masculinity and voting in the 2014 or 2016 congressional elections. This suggests that fragile masculinity has now become a stronger predictor of voting behavior.

Notably, fragile masculinity was unrelated to support for female candidates in the 2018 elections, once we accounted for the fact that female candidates are more likely to be Democrats than Republicans. I, therefore, appears that fragile masculinity doesn’t reduce support for female candidates but rather increases support for Republican candidates of any gender.

Our data suggests that fragile masculinity is a critical feature of our current politics. Nonetheless, points of caution are in order.

First, the research reported here is correlational. We can’t be entirely sure that fragile masculinity is causing people to vote in a certain way. However, given that experimental work has identified a causal connection between masculinity concerns and political beliefs, we think the correlations we’ve identified are important.

Second, it remains to be seen whether any link between fragile masculinity and voting will persist after Trump exits the national stage. We suspect, however, that Trump’s re-engineering of the GOP as a party inextricably tied to many Americans’ identity concerns — whether based on race, religion or gender — will ensure that fragile masculinity remains a force in politics.